1. Field of the Invention
This invention relates to electric power distribution systems and more particularly to meter centers in which power delivered to multiple users is separately metered. Specifically, it relates to configurations of and mountings for supply and tenant buses and to arrangements for connecting meters to both of these buses.
2. Background Information
Meter centers are used for metering electric power delivered to multiple tenants from a common feeder system. Typically, the meter center includes an upright cabinet forming an enclosure divided into side-by-side meter and disconnect switch compartments. Feeder buses, typically three phase buses and a neutral connected to the utility lines, extend horizontally through the rear of the cabinet. The meter compartment has a pair of vertical supply buses connected to a selected pair of the feeder phase buses by phase balancers, so named because connections can be made to selected phases to generally balance the feeder bus phase currents. The vertical or supply buses can include a neutral bus if the meters have a neutral connection.
A pair of tenant buses for each metered circuit extends horizontally from the disconnect switch compartment into the meter compartment. A meter socket mounts a meter in the meter compartment for each tenant circuit and electrically connects the meter to the supply buses and the tenant buses. Commonly used electrical connections on the meter socket include single ended plug-in jaws which are engaged by stabs on the meter. The connectors which incorporate the plug-in jaws are bolted to the socket plate and to either a supply bus or a tenant bus. The four power conducting connectors have a total of about 20 bolted connections in the current path. Such connections require labor to complete and are subject to heating if they become loose. Providing adequate standoff clearance between, and routing for, the closely spaced orthogonally oriented vertical and tenant buses presents additional challenges in the design of meter centers. Furthermore, proper support must be provided for the socket and the buses to withstand the forces applied during installation and removal of the meter, particularly to prevent shorting of the bus bars.
There is a need, therefore, for an improved meter center which eliminates current carrying joints requiring fasteners which can become loose between the meters and the supply and tenant buses.
There is also a need for such an improved meter center which reduces the labor required to install and remove the meter sockets.
There is an additional need for such a meter center in which the components are firmly supported to prevent displacement during installation and removal of the socket assemblies and meters.